Experiment-supported modelling of salt marsh establishment

• Published in: Ocean & coastal management 2019-02, Vol.168, p.238-250
• Main Authors: Poppema, Daan W., Willemsen, Pim W.J.M., de Vries, Mindert B., Zhu, Zhenchang, Borsje, Bas W., Hulscher, Suzanne J.M.H.
• Format: Article
• Language: English
• Subjects: Design tool; Ecological engineering; Seedling establishment; Vegetation dynamics; Windows of opportunity framework
• ISSN: 0964-5691; 1873-524X
• DOI: 10.1016/j.ocecoaman.2018.10.039

Recently, the use of salt marshes in front of hard structures is increasingly proposed as a more sustainable coastal protection measure. Yet, salt marsh restoration and creation is often hampered by the lack of a thorough understanding of initial vegetation establishment. Recent studies highlight the importance of bed level change for salt marsh development. In this study we continue the examination of the impact of bed level change on salt marsh development, focussing on the prediction of salt marsh establishment and the implications for coastal management. First, a test with Spartina anglica seedlings (Cordgrass) in a wave flume showed that long-term (seasonal) bed level change is more important for seedling survival than direct wave impact at the shoot. Therefore, we subsequently incorporated bed level change in the Windows of Opportunity (WoO) framework. Lastly, this revised WoO framework was applied to the design of the Marconi pioneer salt marsh (The Netherlands). Combining the WoO framework with a morphodynamic model (Delft3D) showed its potential for salt marsh design. The framework can be used to determine whether salt marsh establishment is possible, to find out which conditions are limiting establishment and to design engineering measures creating the conditions that facilitate salt marsh establishment. •The survival of Spartina anglica seedlings is sensitive to bed level change.•Bed level change is included in the revised Windows of Opportunity (WoO) framework to better predict vegetation growth.•Applying the WoO framework to a marsh creation project showed the need for wave dampening measures.•The WoO framework is a suitable design tool for salt marsh restoration/creation.